Being the leader of the free world is an expensive proposition. And the costs don't stop once you leave the White House.

The government spent nearly $3.7 million on former presidents in 2012, according to an analysis just released by the nonpartisan Congressional Research Service. That covers a pension, compensation and benefits for office staff, and the government also picks up the tab for other costs like travel, office space and postage.

The costliest former president? George W. Bush, who clocked in last year at just over $1.3 million.

The $3.7 million taxpayers shelled out in 2012 is about $200,000 less than in 2011, and the sum in 2010 was even higher. It's a drop in the bucket compared with the trillions the federal government spends each year.

Still, with ex-presidents able to command eye-popping sums for books, speaking engagements and the like in their post-White House years, the report raises questions about whether the U.S. should provide such generous subsidies at a time when spending cuts and the deficit are forcing lawmakers and federal agencies to seek ways to cut back.

in 1994, Clinton dialed back the Secret Service protection to 10 years post-office. Obama restored lifetime protection to Bush, himself, and all subsequent presidents by signing a bill in January of this year.

And there's a cap on how much the presidents get to spend on their staff.